1. Field of the Invention
The present invention relates to a safety binding for a ski boot. More particularly, the invention relates to a binding, particularly a rear binding, which is adapted to retain one end of the boot, particularly its heel, on the ski, and to free this end when the boot exerts a force exceeding a predetermined threshold on the binding.
2. Description of Background and Relevant Information
Bindings of this type are known which comprise a body attached to the ski, directly or by means of longitudinal adjustment means, and a movable jaw which is journalled with respect to the body around a transverse axis. Energization means further assure the elastic return of the jaw in the direction of the ski.
A binding of this type is for example described in French Pat. No. 2,238,060.
Such bindings assure a satisfactory safety for the skier, but they have the disadvantage of having an elastic extent of small amplitude. The elastic extent designates, in current terms, the distance which the end of the shoe under consideration can space itself vertically from the ski, before causing the release of the binding, and thus its liberation.
Likewise bindings are known whose jaw and body constitute a one-piece assembly, journalled in rotation around a transverse axis at the end of two lateral arms, these two arms being themselves journalled with respect to the ski at the level of their other end.
Such a binding is for example described in French Pat. No. 2,258,876.
The bindings of this type have an elastic extent of an increased amplitude, but a poorer retention of the foot than the preceding bindings. The retention of the foot corresponds to the firmness with which the shoe is returned towards the ski at the beginning of its elastic extent.
The retention of the foot of certain bindings of this type has been improved by adjusting the elastic return of the binding. The elastic return designates, in current terms, the longitudinal sliding of the body of the binding on a slide and the elastic return of this body towards the other binding, which causes the jaw of the binding to exert on the end of the shoe a longitudinal pressure directed towards the other binding. It is known that the elastic return is particularly advantageous to absorb the flexional movements of the ski without inordinately biasing th release mechanism of the binding.
One of the means to compensate for the absence of retention of the foot by the elastic return consists of adopting a limited extent of retraction for the binding, and utilizing elastic return springs of low rigidity. In this manner, as soon as the boot is inserted, the binding retracts and abuts in retraction. Such a construction has the disadvantage that, during skiing, the flexional movements of the ski cannot be absorbed by the elastic return of the binding, because the binding is in abutment, and as a result it is the release mechanism which operates.
Another compensation means consists of rigidifying the return springs with elastic retraction. Such a construction however has the same disadvantage as previously, i.e., that the flexional movements of the ski are absorbed partially by retraction springs and principally by the release mechanism of the binding.
Likewise, the bindings of this type have the disadvantage of requiring auxiliary return springs to bring back the arms and the body of the binding in the direction of the ski.